Chronopharmacologic Cancer Treatment with an Angiogenic Vessel-Targeted Liposomal Drug

Antineovascular therapy (ANET), which eradicates angiogenic endothelial cells by specifically delivered anticancer drugs to tumor cells to obtain complete cutoff of blood supply, is an effective modality for cancer treatment. Since the expression of vascular endothelial growth factor (VEGF) in hypoxic tumor cells is known to fluctuate in a circadian oscillation, we investigated the chronopharmacologic treatment of tumors with ANET. Adriamycin-encapsulated liposomes modified with the Ala-Pro-Arg-Pro-Gly (APRPG) peptide (APRPG-LipADM) were prepared, after the APRPG peptide had been shown to have affinity to angiogenic sites. Colon 26 NL-17 tumor-bearing mice were injected three times with APRPG-LipADM at Zeitgeber time (ZT) 2, 8, 14, and 20 where ZT 0 was the time lights were turned on, and tumor growth was monitored. Tumor growth suppression changed with dosing time and was significantly (p